import express from "express";
import bodyParser from "body-parser";
import crypto from "crypto";

const app = express();
app.use(bodyParser.json());

/* ===== ENV ===== */
const PROJECT = process.env.PAKASIR_PROJECT;
const API_KEY = process.env.PAKASIR_API_KEY;
const WEBHOOK_SECRET = process.env.WEBHOOK_SECRET || "pakasir";

if (!PROJECT || !API_KEY) {
  throw new Error("PAKASIR_PROJECT & PAKASIR_API_KEY wajib diisi");
}

/* ===== MEMORY STORE ===== */
const transactions = new Map(); // order_id => { amount, status }
const clients = new Map();      // order_id => [res]

/* ===== SSE HELPER ===== */
function sendEvent(order_id, payload) {
  const arr = clients.get(order_id) || [];
  for (const res of arr) {
    res.write(`data: ${JSON.stringify(payload)}\n\n`);
  }
}

/* ===== CREATE ===== */
app.post("/create", async (req, res) => {
  try {
    const { amount } = req.body;
    if (!amount || amount < 1000) {
      return res.status(400).json({ error: "amount minimal 1000" });
    }

    const order_id = `INV-${Date.now()}`;

    const r = await fetch("https://app.pakasir.com/api/transactioncreate/qris", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({
        project: PROJECT,
        api_key: API_KEY,
        order_id,
        amount
      })
    });

    const j = await r.json();
    const payment = j.payment || j;

    const qris = payment.payment_number || j.qris_string;
    if (!qris) {
      return res.status(500).json({ error: "gagal create qris", raw: j });
    }

    transactions.set(order_id, {
      amount,
      status: "PENDING"
    });

    res.json({
      success: true,
      order_id,
      amount,
      qr_url: `https://quickchart.io/qr?text=${encodeURIComponent(qris)}&size=500`
    });
  } catch (e) {
    console.error(e);
    res.status(500).json({ error: "create error" });
  }
});

/* ===== SSE REALTIME ===== */
app.get("/events/:order_id", (req, res) => {
  const { order_id } = req.params;

  res.writeHead(200, {
    "Content-Type": "text/event-stream",
    "Cache-Control": "no-cache",
    Connection: "keep-alive"
  });
  res.write("\n");

  const arr = clients.get(order_id) || [];
  arr.push(res);
  clients.set(order_id, arr);

  req.on("close", () => {
    const left = (clients.get(order_id) || []).filter(r => r !== res);
    if (left.length === 0) clients.delete(order_id);
    else clients.set(order_id, left);
  });
});

/* ===== WEBHOOK ===== */
app.post("/webhook", (req, res) => {
  try {
    const body = req.body;
    const order_id = body.order_id || body.payment?.order_id;
    let status = body.status || body.payment?.status;

    if (!order_id || !status) {
      return res.status(400).send("invalid payload");
    }

    status = status.toUpperCase();

    if (transactions.has(order_id)) {
      transactions.get(order_id).status = status;
    }

    sendEvent(order_id, { order_id, status });
    res.json({ ok: true });
  } catch (e) {
    console.error(e);
    res.status(500).send("webhook error");
  }
});

/* ===== STATUS (FIXED) ===== */
app.get("/status/:order_id", async (req, res) => {
  try {
    const { order_id } = req.params;
    const tx = transactions.get(order_id);

    if (!tx) {
      return res.json({ order_id, status: "NOT_FOUND" });
    }

    // kalau sudah PAID dari webhook → langsung return
    if (tx.status === "PAID" || tx.status === "SUCCESS") {
      return res.json({ order_id, status: tx.status });
    }

    // fallback polling (WAJIB amount)
    const params = new URLSearchParams({
      project: PROJECT,
      api_key: API_KEY,
      order_id,
      amount: tx.amount
    });

    const r = await fetch(
      `https://app.pakasir.com/api/transactiondetail?${params}`
    );
    const j = await r.json();
    const data = j.transaction || j;
    const status = (data.status || "PENDING").toUpperCase();

    tx.status = status;
    transactions.set(order_id, tx);

    res.json({ order_id, status });
  } catch (e) {
    console.error(e);
    res.status(500).json({ error: "status error" });
  }
});

/* ===== HEALTH ===== */
app.get("/", (req, res) => {
  res.json({
    name: "Pakasir Realtime Gateway",
    status: "running"
  });
});

/* ===== START ===== */
const PORT = process.env.PORT || 7860;
app.listen(PORT, () => console.log("RUNNING ON", PORT));